This invention relates to golf balls. In particular, it relates to a three-piece golf ball having playability characteristics which are improved relative to state-of-the-art balls.
According to United States Golf Association (U.S.G.A.) rules, a golf ball may not have a weight in excess of 1.620 ounces or a diameter smaller than 1.680 inches. The initial velocity of U.S.G.A. "regulation" balls may not exceed 250 feet per second with a maximum tolerance of 2%. Initial velocity is measured on a standard machine kept by the U.S.G.A. wherein a projection on a wheel rotating at a defined speed hits a test ball, and the length of time it takes the ball to traverse a set distance after impact is measured. U.S.G.A. regulations also require that a ball not travel a distance greater than 280 yards when hit by the U.S.G.A. outdoor driving machine under specified conditions. In addition to this specification, there is a small tolerance for test error.
These specifications limit how far a golf ball will travel in several ways when hit. Increasing the weight of a golf ball tends to increase the distance it will travel and lower the trajectory. A ball having greater momentum is better able to overcome drag. Reducing the diameter of the ball also has the effect of increasing the distance it will travel when hit. This is believed to occur primarily because a smaller ball has a smaller projected area and thus, a lower drag when travelling through the air. Increasing the initial velocity increases the distance the ball will travel.
The foregoing generalizations hold when the effect of size, weight, or initial velocity is measured in isolation. Flight characteristics (influenced by dimple pattern and ball rotation properties), club head speed, radius of gyration, and diverse other factors also influence the distance a ball will travel.
In the manufacture of top-grade golf balls for use by professional golfers and amateur golf enthusiasts, the distance a ball will travel when hit (hereinafter referred to as "distance") is an important design criterion. Since the U.S.G.A. rules were established, golf ball manufacturers have designed top-grade U.S.G.A. regulation balls to be as close to the maximum weight, minimum diameter, and maximum initial velocity as golf ball technology will permit. The distance a ball will travel when hit has, however, been improved by changes in raw materials and by alterations in dimple configuration.